Influence of the Electron Deficient Co-Monomer on the Optoelectronic Properties and Photovoltaic Performance of Dithienogermole-based Co-Polymers - Yau,CP; Fei,Z; Ashraf,RS; Shahid,M; Watkins,SE; Pattanasattayavong,P; Anthopoulos,TD; Gregoriou,VG; Chochos,CL; Heeney,M (ADVANCED FUNCTIONAL MATERIALS, 2014)